An output node (FBN) of a conventional PMIC can merely output an identical direct current (DC) level. When it is desired to control a low level VGL (e.g., different voltage levels are required at the start-up moment and during the operation, or the low level VGL is required when detecting different images or different temperatures), a printed circuit board assembly (PCBA) needs to be provided with an additional control circuit. At this time, the circuits on the PCBA and the layout thereof need to be changed, and more space needs to be provided for elements on the PCBA.